JPS6018862A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To separate quickly and accurately two types of information groups from each other by producing an error detection code to the information group containing a synchronizing signal and adding said detection code to perform the recording as well as the detection of errors by an error detection code. CONSTITUTION:For the signal outputted from a decoder 13, a synchronizing signal pattern is first detected by a synchronizing signal detecting circuit 14. When said pattern is detected, both the discrimination signal and error detection code are supplied to an error detecting circuit 15 from the next data. Thus an error detecting action is carried out. When a correct operation is decided, the data on an information signal block is outputted by an interface circuit 17 under the control of a control circuit 16. If an error is decided, the discrimination signal and its subsequent information signal are not read out. Then the synchronizing signal is detected again.

Description

Detailed Description of the Invention [Field of Application of the Invention J The present invention relates to a signal group separation method for a high-density information recording/reproducing device such as an electronic computer, and particularly relates to a method for separating signal groups in a high-density information recording/reproducing device such as an electronic computer. The present invention relates to an information recording/reproducing device suitable for use in a variety of applications.

[Background of the invention]

Recording media recorded by optical or magnetic means are used as auxiliary storage devices for electronic computers and the like. Although it is essential to reduce the errors in recorded information caused by defects in the recording medium, there is a limit to physically reducing the defects in the recording medium. As a method of improving the properties of such recording media and isometrically improving the error rate of the medium, PCM (PulseCo
de Modulation ) processing is available. For example, a plurality of channels in a first arrangement state are time-series sampled, and the nine PCM sequences are rearranged on the time axis, such as delay interleaving, to obtain a second arrangement state.

In this process, a first check word sequence is generated by supplying one word included in each of the PCM sequences in the first arrangement state to a first error correction encoder, and this first check word sequence and a plurality of A second check word sequence is generated by setting the PCM data sequence of the channel to the above-mentioned second arrangement state and supplying one word included in each to a second error correction encoder.

As a result, double interleaving (arrangement rearrangement) is performed on a word-by-word basis. Interleaving involves transmitting the check words and PCM data included in a common error correction block in a distributed manner, and when returning them to the original arrangement on the receiving side, error words among multiple words included in the common error correction block are This is an attempt to reduce the number a little. In other words, when a burst error occurs during transmission, this burst error can be dispersed. If such interleaving is performed twice, each of the first and second check words constitutes a separate error correction block, so even if an error cannot be corrected in one of the check words, the other check word cannot be corrected. can be used to correct errors, thus further improving the error correction ability.

A case where a medium recorded by the above method is used as a storage device will be described.

Information to be recorded and reproduced is generally handled as a set of bytes (8 bits) (hereinafter referred to as a sector). Therefore, the information string to be recorded should be one sector or more! At least, between the first information group divided into each sector, and the information groups,
The first array is an array obtained by inserting a second information group including a first synchronization signal indicating the delimiter of the first information group and information for identifying the contents of the first information group. , the above-mentioned second arrangement state and second check word sequence are recorded on a recording medium.

When recording in the second arrangement state, a second synchronization signal for identifying the interleaving reference and check word generation block is inserted.

The first arrangement state, in which the medium recorded by the above method is reproduced by adding processing such as error detection and correction, has a low error rate and improves the ll & υ rate of information caused by defects in the medium. The second information group and the first information group are obtained as an alternating array.

Next, accurately separate the first information group and the second information group,
Based on the information contained in the second information group, it is necessary to identify the contents of the first information group obtained in succession. In order to achieve this, the first
A method is used to detect the constituent bit pattern of the synchronization signal from the reproduced first arrangement state, but the same pit pattern is detected in the first information group or the first information group in the second information group. It is said that it also exists in the part excluding the synchronization signal of
This may be mistakenly detected as the first synchronization signal. In such a case, correct b separation between the first information group and the second information group is not performed, and even though the reproduced first arrangement state has a low entertainment rate, Information output to electronic computers, etc. was sometimes incorrect.

[Purpose of the invention]

An object of the present invention is to provide an information recording and reproducing apparatus that accurately separates two types of information groups that are arranged alternately.

[Summary of the invention]

The present invention generates an error detection code for an information group containing a synchronization signal among two types of information groups, records the code with this added, and detects the synchronization signal at the time of playback. The purpose is to also perform error detection using a v4#) detection code.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in the case where an optical digital audio disc is used as a recording medium.

FIG. 1 shows the structure of one sector of information input/output to a computer or the like. In the figure, 1 is an information signal block that is input/outputted as data to a computer, etc., 2 is a synchronization signal indicating the beginning of a sector, 6 is an identification signal block containing information such as the address of the sector, and 4 is an identification signal block. ,
This is an error detection code generated using a predetermined method based on the signal of the identification signal block. These signals are arranged consecutively, and each sector is also arranged consecutively.

During recording, these continuous signals are divided into 8-bit units, and an error correction code is generated and added using a double error correction code sequence, and after interleaving is performed, the signal is recorded on a disc in a predetermined signal format. Many errors occur in the signal played back from the 0 disc due to scratches and dust on the disc, as well as noise in the circuit system, but the above-mentioned interleaving and double error correction The code corrects most signal errors,
The signal arrangement is returned to that shown in FIG.

When a computer, etc. needs data, it often stores the data in a part of a number of consecutive sectors, and the selection of that sector is done by specifying the address of the sector that is needed and then selecting this sector. This is done by extracting the information signal from the sector with the same address as 6.
- Figure 2 shows a block diagram during playback. In the same figure,
10 is a disk, 11 is a motor, 12 is a laser pickup, 13 is a decoder that performs operations such as the above-mentioned correction, 14 is a synchronization signal detection circuit, and 15 is used to detect errors using the above-mentioned error detection code. An error detection circuit 16 is a control circuit that processes the detected identification signal, and 17 is an interface circuit that outputs the detected information signal to the external device 1B.

The signal output from the decoder 16 is first subjected to detection of a synchronization signal pattern by the synchronization signal detection circuit 14. When the synchronization signal pattern is detected here, the identification signal and error detection code are detected by the error detection circuit 1 from the next data.
5, and the erroneous detection operation is performed from time to time. If it is determined to be correct, the interface circuit 17 outputs the data of the information signal block under the control of the control circuit 16. If it is determined to be an error, the synchronization signal detection operation is performed again without reading out the identification signal and the subsequent information signal.

As an example of an error detection code, a cyclic check code (CRCC) is used.
When using this method, if the check code length is set to 32 bits, the probability of an error detection error occurring is about once in 4×109 detection operations, which poses no problem in practice.

By adopting the signal configuration and reproducing circuit configuration described above, it is possible to accurately separate the information signal section and the identification signal section, reduce errors in output data to external equipment, and reduce data output from external equipment. The time required to output data in response to a request can be shortened.

Although this embodiment describes only the case where an optical audio disc is used as the recording medium, the present invention is equally effective with other recording media. Furthermore, the types and code configurations of error detection codes are not limited to the cyclic check codes described in this embodiment, but may also include other codes,
For example, Reed-Solomon codes can also be used.

〔Effect of the invention〕

According to the present invention, since two types of information groups can be separated accurately and quickly, signal errors in the read information group caused by the separation ib are reduced, and the time used for reading is shortened. I can do it.

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[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of recording and reproducing information signal groups;
The figure is a circuit configuration diagram when the present invention is applied to an optical audio disc. 1... Information signal block, 2... Synchronization signal, 6...
・Identification signal block, 4...Error detection code, 10...
- Disk, 13... Decoder, 14... Synchronous signal detection circuit, 15... Error detection circuit, 16... Control circuit. Representative Patent Attorney Akio Takahashi

Claims (1)

[Claims] A first information group and a second information group including identification information of the first information group.
In an information recording/reproducing apparatus that records, records, and reproduces information groups arranged alternately, is it possible to generate and add an error detection code to the second information group during recording? A detection code generation circuit;
an error detection circuit that inspects the second information group and an error detection code added thereto during reproduction; and a separation circuit that separates the first information group and the second information group based on the output of the error detection circuit. An information recording and reproducing device comprising: